Transmission and reception systems are known which comprise a transmitter for transmitting program and attribute information of the program and a receiver for receiving the program and attribute information transmitted by the transmitter and for accumulating part of or whole of the program.
In the transmission and reception system, the attribute information of a program transmitted by the transmitter is information indicating the type of information provided by the transmitter to users.
A high level of secrecy is required for attribute information indicating the type of information provided by the transmitter to users because a broadcast can be received by anybody.
For this reason, when attribute information for which secrecy is a must is to be transmitted to each receiver, the transmitter transmits attribute information which has been coded according to a predetermined coding system to the receiver.
Only receivers having a key to decode the codes can decode the coded attribute information transmitted by the transmitter.
However, there is no guarantee that a coding system will be permanently safe after it is once decided because of recent advances of decoding techniques. A reduction of the safety of a coding system necessitates replacement of IC cards of all receivers.
When a plurality of receivers employ different coding systems, the size of a decoding program in the receivers increases; processes in the program become complicated; and the hardware configuration of the receiver also becomes complicated.
It is an object of the invention to provide a transmitter and a receiver capable of transmitting and receiving attribute information of a program while maintaining a high level of secrecy in a simple hardware configuration without using a coding system.